HisabCalc

Credit Card Payoff

How long a card balance takes to clear at a given monthly payment, and what it costs.

Enter your numbers

Result

Figures are computed on your device; nothing is sent anywhere.

Formula

months = −ln(1 − balance·r ÷ payment) ÷ ln(1+r), r = rate ÷ 1200

How the calculation works

Each month the interest is charged on the balance, the payment settles that first, and only what is left reduces the principal. At 22% the monthly rate is 1.833%, so on 5,000 the first month's interest is 91.67 and a 200 payment cuts the debt by just over 108. Early on most of the payment is rent on the money, which is why the balance barely seems to move.

The formula folds that month-by-month loop into a single logarithm, and what it turns on is the ratio of payment to monthly interest rather than the balance alone. Scale the balance and the payment together and the time is unchanged: 5,000 at 200 a month and 10,000 at 400 both take 34 months, though the interest doubles with the balance.

There is a hard floor. If the payment does not exceed the monthly interest the balance never falls and no number of months clears it, so the tool refuses instead of returning a huge figure. The break-even payment here is the monthly interest, about 91.67; a payment of 100 clears the 5,000 but takes 137 months and costs 8,700 in interest.

Common mistakes

When to use it

Worked example

A 5,000 card balance at 22% paying 200 a month takes 34 months and costs 1,800 in interest.

Months 34
Years 2.83
Monthly interest 91.67
Total paid 6,800.00
Total interest 1,800.00

Common questions

What if I only pay the minimum?

That is the trap. At 22%, paying only the minimum takes years and the interest can exceed the original balance. Put a small number in above and watch it.

What if my payment is below the monthly interest?

Then the debt never clears and grows instead. The calculator stops rather than showing a number, because that would mislead.

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Last updated: 2026-09-29